The present invention relates to a nozzle through which a fluid such as a paste-like solder can escape and flow in a desired condition, and particularly to a structure of an outlet of such nozzle for a soldering apparatus.
When electronic devices, for example, are manufactured, as shown in FIG. 1, a metal electronic assembly (hereinafter simply referred to as "metal plate") P such as an electrostatic shield plate or a magnetic shield case is soldered vertically to the end face of a printed-circuit board or a chassis (hereinafter simply referred to as "base") B on which electronic circuits are fabricated at several joint portions in such a manner that the base B and the metal plate P make two or three surfaces which are perpendicular to each other. In FIG. 1, reference letters S denote solder mass obtained after the whole of the assembly with the solders coated thereon. The solder S has been heated in a furnace at a high temperature and soldered in next process.
In general, this paste-like solder is adhered or coated by using a nozzle 10 shown in FIGS. 2A and 2B.
As shown in FIGS. 2A and 2B, the nozzle 10 comprises a nozzle body 12 of a straight pipe shape, a supply opening 11 formed with the nozzle body 12, a tip end portion 13, and an outlet 14 formed by cutting the tip end portion 13 of the nozzle body 12 at an angle of 45.degree., for example.
When the paste-like solder S is coated on an assembled joined member so as to form two vertical surfaces, i.e., over two surfaces including a corner portion C of the base B and the metal plate P by using the nozzle 10, one side surface 12B of the nozzle body 12 is brought in contact with the surface of the metal plate P and the tip end portion 13 of the nozzle 10 is brought in contact with the surface of the base B in such a manner that the outlet 14 is opposed to the corner portion C (see FIG. 3A).
Accordingly, as shown in FIG. 3A, although the cut surface of the tip end portion 13 is opposed at an inclination angle of 45.degree. to the corner portion C of the base B and the metal plate P united so as to form the two surfaces perpendicular to each other, the direction in which the paste-like solder pressured out by a squeegee (not shown) from the outlet 14 is the direction same as the direction in which the paste-like solder S guided by an inner wall 12A of the nozzle body 12 flows, as shown by an arrow Y in FIG. 3A. Initially, the paste-like solder S directly flows toward the surface of the base B. Then, the paste-like solder S that was brought in contact with the surface of the base B is pushed toward the corner portion C, whereafter it is accumulated over the two surfaces including the corner portion C by a necessary amount (see FIG. 3B).
However, because the base B is warped, the nozzle 10 is floated or a jig has a defect, a fluctuation of dimension occurs between the tip end portion 13 of the nozzle 10 and the surface of the base B or between the one side surface 12B of the nozzle 10 and the surface of the metal plate P. As a result, it is frequently observed that the paste-like solder S cannot be satisfactorily coated on the corner portion C.
Specifically, FIG. 4A shows the state in which a relatively large gap G exists between the tip end portion 13 of the nozzle 10 and the base B due to a fluctuation of dimension between the tip end portion 13 of the nozzle 10 and the base B. When the paste-like solder is coated in the state shown in FIG. 4A, the paste-like solder that flowed from the outlet 14 is dropped onto the base B and cannot flow toward the direction of the corner portion C. As a result, the paste-like solder mass S thus escaped is accumulated in the place away from the corner portion C and remains accumulated on the surface of the base B as shown in FIG. 4B.
When the paste-like solder is pushed out from the nozzle 10 by the squeegee, if a flat-type squeegee is used, a speed at which the paste-like solder flows from the outlet 14 of the nozzle 10 decreases as compared with the case that a roller-type squeegee is used. As a consequence, the paste-like solder thus escaped becomes difficult to flow toward the corner portion C. Therefore, the metal plate P cannot be soldered to the base B. There is then the possibility that a poor soldering will occur.
If the paste-like solder is coated when a relatively large gap G is produced between the one side surface 12B of the nozzle 10 and the surface of the metal plate P between a fluctuation of a dimension caused between the one side surface 12B of the nozzle 10 and the surface of the metal plate P as shown in FIG. 5A, similarly, then the paste-like solder flowed from the outlet 14 is dropped onto the base B and cannot flow toward the direction of the corner portion C. As a result, the paste-like solder mass S thus escaped is accumulated in the place away from the corner portion C and remains accumulated on the surface of the base B as shown in FIG. 5B. As a consequence, the paste-like solder thus escaped becomes difficult to flow toward the corner portion C. Therefore, the metal plate P cannot be soldered to the base B. There is then the possibility that a poor soldering will occur.
When the paste-like solder is coated and accumulated by using the nozzle 10, it is frequently observed that the above-mentioned disadvantage of such accumulated solder occurs. As a consequence, after the paste-like solder was coated and accumulated, the user should always inspect the soldered part and correct a poor soldered part if any.